19,950 research outputs found
Obesity paradox versus frailty syndrome in first-ever ischemic stroke survivors
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A model-independent dark energy reconstruction scheme using the geometrical form of the luminosity-distance relation
We put forward a new model-independent reconstruction scheme for dark energy
which utilises the expected geometrical features of the luminosity-distance
relation. The important advantage of this scheme is that it does not assume
explicit ansatzes for cosmological parameters but only some very general
cosmological properties via the geometrical features of the reconstructed
luminosity-distance relation. Using the recently released supernovae data by
the Supernova Legacy Survey together with a phase space representation, we show
that the reconstructed luminosity-distance curves best fitting the data
correspond to a slightly varying dark energy density with the Universe
expanding slightly slower than the Lambda CDM model. However, the Lambda CDM
model fits the data at 1 sigma significance level and the fact that our best
fitting luminosity-distance curve is lower than that of the corresponding
Lambda CDM model could be due to systematics. The transition from an
accelerating to a decelerating expansion occurs at a redshift larger than
z=0.35. Interpreting the dark energy as a minimally coupled scalar field we
also reconstruct the scalar field and its potential. We constrain
using the baryon acoustic oscillation peak in the SDSS luminous
red galaxy sample and find that the best fit is obtained with
, in agreement with the CMB data.Comment: 10 pages, 18 figure
Compressibility of bilayer graphene
Bilayer graphene is a recently isolated and intriguing class of many-body
systems with massive chiral quasiparticles. We present theoretical results for
the electronic compressibility of bilayer graphene that are based on a
four-band continuum band structure model combined with a random phase
approximation treatment of electronic correlations. We find that the
compressibility is strongly suppressed by electron-electron interactions at low
carrier densities. Correlations do not lead to any qualitative new features,
but are crucially important for a quantitative understanding of this
fundamental thermodynamic property of graphene bilayers.Comment: 9 pages, 5 figure
Cardiac manifestations of PRKAG2 mutation.
BACKGROUND:The Protein Kinase AMP-Activated Non-Catalytic Subunit Gamma 2 (PRKAG2) cardiac syndrome is characterized by glycogen accumulation in the cardiac tissue. The disease presents clinically with hypertrophic cardiomyopathy (HCM), and it is often associated with conduction abnormalities. CASE PRESENTATION:A 23 year-old female with history of Wolff-Parkinson-White (WPW) and HCM presented for evaluation after an episode of Non-ST Elevation Myocardial Infarction (NSTEMI). The patient was found to have severe coronary bridging on angiography and underwent an unroofing of the left anterior descending artery (LAD). Due to the constellation of symptoms, the patient underwent genetic testing and a cardiac muscle biopsy. Genetic testing was significant for an Arg302Gln mutation in the PRKAG2 gene. Cardiac tissue biopsy revealed significant myocyte hypertrophy and large vacuoles with glycogen stores. CONCLUSION:The pathologic and genetics findings of our patient are consistent with PRKAG2 syndrome. Patients presenting with conduction abnormalities and suspected HCM should be considered for genetic testing to identify possible underlying genetic etiologies
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